Xiaomi smartphones have long proven to be reliable devices, but owners often face the nuances of touch systems. One of the most common problems is the incorrect operation of the proximity sensor, which is responsible for turning off the screen during a conversation. If the screen does not go out when you hold the phone to your ear, or, conversely, goes out on its own, this creates serious discomfort when communicating.
In this article, we will discuss in detail how to test the proximity sensor on Xiaomi using built-in system tools and third-party applications. You will learn why the Proximity Sensor malfunctions, how to conduct deep calibration through the engineering menu, and what to do if software methods do not help restore the correct operation of the device.
Don’t ignore this malfunction, as it can lead to accidental cheek pressing, resetting calls or switching on the standby mode in your pocket. Proper diagnosis will help you understand whether you need firmware, simple adjustment or physical repair of the module.
Principle of operation and location of the sensor
The proximity sensor is an infrared sensor that emits invisible light and reads its reflection from objects. In Redmi and POCO smartphones, this element is most often hidden under the top of the display or displayed in a separate hole in the frame. When you hold the phone to your head, the sensor picks up the reflected signal and tells the MIUI system to extinguish the matrix.
There are two main types of sensors used in the Chinese manufacturer’s lineup: budget models often feature a virtual sensor that works on the basis of accelerometer and gyroscope data, which sometimes leads to false positives when sharp movements. Flagship and mid-budget models are equipped with a full-fledged infrared module that requires clean space above the screen.
⚠️ Warning: Protective glass with a wide black frame or poor quality film can block the IR emitter, which will make the system believe that the phone is constantly in the ear.
Understanding the physics of the process is important for proper diagnosis, and if there is an obstacle in the path of the beam — whether it is dirt, greasy marks or thick glass — calibration may not help, and you may need to physically clean the sensor area or replace the protective coating.
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Use a soft microfiber to wipe the top of the screen before testing to rule out contamination.
Using the CIT Engineering Menu for Diagnostics
The most reliable way to test the proximity sensor on Xiaomi is to use the built-in CIT (Customer Inspection Test) menu, which is available on all devices with the MIUI and HyperOS shell, regardless of the regional version of the firmware, and allows you to test each component of the smartphone in isolation mode.
You don't need root rights or a computer connection to log into the diagnostic menu, just open the standard Phone app and enter a special combination of characters, and after you enter the code, the system automatically goes to the hidden settings section, where you have a full list of available tests.
Type the following code into the dialer: ##6484##. If the code didn't work, try the alternative ##4636##, although it's more commonly used to check the network and battery. In the list that opens, look for Proximity Sensor or Approximation Sensor.
☑️ Check through CIT
Inside the test, you'll see a numerical value that changes in real time. When the hand closes the top of the screen, the value should change (e.g., from 5.0 to 0.0 or vice versa, depending on the model). If the numbers "dance" or do not respond to movements, this indicates a software failure or hardware malfunction.
| Parameter | Normal condition | Signs of malfunction |
|---|---|---|
| Reaction on the hand | Instant change of values | Delay or lack of response |
| Indications in peace | Stable number (e.g. 5.0) | Chaotic change of numbers |
| Test screen | Green when successful | Red color or test error |
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If the sensor shows stable values in the CIT menu and reacts to the hand, but the screen does not go out in the calls - the problem lies in the system settings or application conflict.
Customization and calibration through a hidden menu
If the initial check has been inconsistent, you need to calibrate, a process where you train the system to understand what is near and far, a procedure that is often solved automatically on Xiaomi smartphones, but sometimes requires manual intervention.
To start calibration in the same CIT engineering menu, after selecting the Proximity Sensor, you press the Calibration button (if available in your version of MIUI). You will try to close the sensor with your finger, and then remove your hand. The system will record minimum and maximum lighting/reflection values.
What to do if there is no Calibration button?
After successful calibration, be sure to restart the device. A conventional screen shutdown may not be enough, since sensor drivers only load when the system starts. Restart will fix the new parameters in non-volatile memory.
It's worth noting that frequent calibrations unnecessarily can bring down factory settings. Use this method only when you're sure there's a problem. If things haven't improved after calibration, it may be physical damage to the plume or the module itself.
- 📱 Make sure that during calibration the phone is on a flat surface.
- 🖐️ Do not touch the sensor hole directly with your finger, use your palm, closing the top third of the screen.
- 🔄 Repeat the procedure. 2-3 If the first result is not satisfactory.
Third-party applications for deep testing
The built-in MIUI is good, but sometimes it's too big a picture. You can use Google Play to analyze sensor behavior in more detail, and it lets you see the graph of the change in values and see when the sensor blinks.
One of the most popular tools is the Proximity Sensor Reset/Fix app, which not only tests but also tries to software correct driver errors. Another useful tool is the Sensor Test, which shows all sensors in real time.
Using third-party software is especially important if you plan to install custom firmware or modified recovery, and these apps help you understand whether the hardware is working at the basic level, regardless of the operating system settings.
When installing these programs, pay attention to the permissions you're asking for. They need access to sensors to work, but they don't have to require access to contacts or a microphone for no good reason. Data security when using diagnostic software is also important.
Typical causes of failures and program conflicts
Why does a seemingly functional sensor stop working? Often it's not a malfunction, but a software conflict. The MIUI shell has many optimization features that can interfere with standard modules, such as In-Pack mode, which may not work properly due to algorithm errors.
Another common reason is system updates: After an Android or MIUI update, users often notice that the screen starts to go out ahead of time or, conversely, does not respond to the approach, this is due to the fact that new drivers may not be compatible with the current calibration.
⚠️ Attention: Installing third-party memory “optimizers” and “cleaners” often leads to the forced closure of system processes responsible for sensors, which causes them to fail.
Also worth checking is the special features settings. In Settings → Advanced settings → For people with disabilities, functions that block the sensor can be activated. Turning off unused options sometimes brings the sensor back to life.
If you use Themes, try switching to the standard Classic theme, and some customizations change the system files that handle proximity sensor signals, causing a breakdown.
Hardware problems and methods of their elimination
When software methods are powerless, you have to consider hardware reasons. In Redmi Note and POCO X-series smartphones, the proximity sensor plume often fails after falls or moisture hits. Even a micro-crack in the board can disrupt contact.
If the phone was recently opened to replace the battery or screen, it is possible that the wizard forgot to plug the plume or damaged it during assembly, in such cases, checking the proximity sensor on Xiaomi shows a complete lack of reaction (values do not change at all).
- 💧 Moisture: Even a drop of sweat or rain can cause a short circuit in the sensor area.
- 🔨 Mechanical impact: from the impact can move the connector of the plume inside the body.
- 🏭 Factory marriage: In rare cases, the module itself may be defective from the moment of purchase.
For home diagnosis, you can gently (indiscriminately) tap your finger on the top of the case in the speaker area, and if the readings on the engineering menu start to jump, then the contact is broken and the intervention of the service center is required.
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If the sensor shows 0.0 or 5.0 unchanged in the engineering menu for any action, and the calibration does not help, a physical breakdown of the module is likely.